A Printable Humidity Sensing Material Based on Conductive Polymer and Nanoparticles Composites

Abstract

To monitor humidity, the polymer-based humidity sensing material has become an emerging candidate because of its low-cost and low-power characteristics. To implement polymer sensing materials, however, the fabrication capability and stability are major concerns. In this work, an inkjet printable humidity sensing material, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), is developed to improve the fabrication capability. Besides, different kinds of nanoparticles, SiO₂ and aluminum zinc oxide (AZO), are also employed to enhance the stability and sensitivity to humidity sensing. Based on experimental results, the sensitivity can be improved by 100%; the stability can also be noticeably enhanced. To understand the sensing mechanism, X-ray diffraction (XRD), Fourier transforms infrared diffraction (FTIR), and photoluminescence (PL) spectrometer measurements are performed. Based on these material investigations, the sensing enhancement is due to physical adsorption of the blending nanoparticles. This work proposes a high sensitivity and low cost humidity sensing material for different applications.